Former Chelsea boss Ruud Gullit has questioned the timing of the appointment of Mark Hughes at QPR.
Hughes takes charge for the first time on Sunday when QPR travel to resurgent Newcastle.
But Gullit told the London Evening Standard: "When you change managers in the middle of a season, in the first matches there is always a change. Naturally there is a bit of a response from the players and there is a new energy. But all of a sudden it tends not to happen any more. The League Managers' Association has done a report which shows this.
"It is a quick fix, not a long-term solution, most of the time. That is what the figures say and they don't lie. You always hope that things go better but it doesn't necessarily happen. Most of the time it doesn't go better over the long-term than it was in the first place. It is a gamble, changing manager always is. The people in the boardroom don't know how it is going to work out. They just hope it will go well."